This invention relates to a new and improved apparatus for dispensing a predetermined amount of fluid sealant into a can end recess for subsequent air tight attachment to a metallic can body in the manufacture of beverage containers and the like.
The current state of the art for applying a uniform bead of sealant to a can end member on a high speed production line for can ends, has progressed to the point of utilizing available electro pneumatic nozzles attached to mechanical support devices which are mounted in relatively fixed positions. The actuation of the dispensing of fluid sealant has generally been accomplished by means of an assembly which senses the proximity of the can end to the dispensing nozzle, when the can end is being rotated. Fluid sealant is then dispensed as the can end groove for receiving the sealant is rotated underneath the dispensing nozzle.
Adjustment of the proximity sensing device and the positioning of the arm is critical to the high speed operation of such a device. In the past, the proximity of the can end to the dispensing nozzle was sensed by the movement of a rocker arm assembly, which physically engaged the top of a can lid hold down pad shaft. As is customary with such devices, a considerable amount of play could develop requiring constant adjustment and attention thus decreasing the overall output of can ends from a production line incorporating such a device. The result of improper adjustment would be the dispensing of too much sealant or not enough sealant to accomplish the purpose for which the sealant is used. The subsequent container assembled from the can end might then not be properly sealed which could cause premature spoilage of the contents where perishable. In the same manner, the improper location of the nozzle over the can end being spun may cause the sealant to be placed in the wrong location of the can member, i.e., on portions of the can end other than the intended groove or recess, thus defeating the proper sealing function when the groove is subsequently attached to the open end of a can body.
It can be seen, therefore, that it is of critical importance that the positioning of a dispenser for fluid sealant over the groove in a can end be accurately and repeatedly accomplished. Likewise, the apparatus for providing the precise location should be capable of being serviced easily and returned to its operative position with a minimum of time spent for adjustment of the apparatus.
It is also highly desirable that a preferred apparatus for dispensing fluid sealant include as an integral portion thereof further apparatus for sensing can end proximity, which eliminates the drawback of complicated mechanical linkage which, as previously discussed, is prone to certain deficiencies in use.
Further, it is desirable to reduce the number of external pipes and lines servicing the dispenser gun and the controls for actuation of the flow of fluid sealant from the dispenser gun. External lines only tend to make repair and adjustment cumbersome by their presence and are prone to abuse and frequent repair or replacement during the operation of a high speed can end fabricating operation.
The present invention aims to eliminate most of the aforementioned problems by providing an apparatus which is capable of firmly supporting a fluid dispensing gun which is actuatable by improved can end sensing means, both of which are mounted on a support arm which is firmly located as to lateral position, but supported at its extremity by both horizontal and vertical pivoting means to enable the arm when serviced to be removed from its operative position over the can end to a position sufficiently removed from the work station to facilitate adjustment, cleaning or the like when required, and then simply and easily returned to a precise location for subsequent use.
These advantages are accomplished by providing a base plate positioned on a work table adjacent the can end feed transport means which will generally be bringing can ends from a stamping press. The base plate has mounted thereon pivoting means for supporting a dispenser arm that permits arcuate movement of the dispenser arm in both the horizontal and vertical planes, and clamping means for positioning the dispenser arm in a predetermined location generally transverse to the can end feed direction. The dispenser arm of the present invention contains at the end opposite the pivot means, a can end hold down pad assembly comprising, proximity sensing means responsive to actuation by the upward vertical engagement of a can end by reciprocal means located in the can end feed path, which reciprocal means moves the can end upward against the hold down pad of the assembly of the present invention while the can end is being rotated, electro-pneumatic means also mounted on the dispenser arm and responsive to the signal generated by the proximity sensing means for providing pneumatic pressure to preferrably lift a needle valve within a sealant dispenser gun to permit the discharge of fluid sealant from a supply under pressure, out through the nozzle of the dispenser gun and into the groove of the rotating can end. The speed of rotation and time of sealant discharge are adjustable to coincide with exactly one revolution of the can end under the dispensing gun while sealant is being discharged.
Accordingly, by use of the apparatus of the present invention, sealant can be properly applied to can ends on a can end feed transport means at each station equipped with the apparatus herein described at rates in excess of 400 can ends per minute.